The popularity of functional foods and nutraceuticals has surged owing to the heightened consumer awareness and prevalence of lifestyle diseases. Nutrigenomics offers a clear and science based perspective of the effect of functional foods and nutraceuticals on the gene expression and human health. This chapter explores the role of bioactive food components in modulating genetic mechanisms such as transcription factors, epigenetic changes, and microRNAs, with the aim of preventing and managing chronic diseases. It distinguishes between functional foods and nutraceuticals, discusses their natural sources, and outlines their molecular and clinical effects on human health. It also discusses about the safety and efficacy of nutraceuticals, market trends, emerging opportunities and challenges in a brief way. The integration of nutrigenomics into food science provides a foundation for precision dietary interventions and offers exciting prospects for the development of targeted health solutions in the modern era.